The discussion
in the previous slides (12-16) leads to the conclusion that the critical proportions of
vaccination required to eradicate an infection (PC) can be calculated for
specified infections in specified populations (from the average age at infection prior to
vaccination (A) and life expectancy at birth (L) through the basic reproductive rate (R0)).

This
slide presents approximate estimates of the order of magnitude of the critical proportions
of vaccination (PC), derived from several studies.

For successful eradication, these levels of vaccination coverage should be achieved in
all sectors or of the population; a national average is not enough, as the microorganism
may be sustained in "pockets" of the population where R remains >=1.